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Do not retrieve all columns with Elastic search query

I have an Elastic search query and I would like to retrieve a certain column, not all.
I make my request in java with BoolQUEryBuilder which gives:
BoolQueryBuilder query = boolQuery();
query.must(wildcardQuery('value', value + "*"));
return findAll(query);
The method findAll :
protected List<T> findAll(final BoolQueryBuilder query) {
Query searchQuery = (new NativeSearchQueryBuilder()).withQuery(query).build();
SearchHits<T> searchHits = this.elasticsearchRestTemplate.search(searchQuery, this.getClazz(), this.elasticsearchRestTemplate.getIndexCoordinatesFor(this.getClazz()));
return (List)SearchHitSupport.unwrapSearchHits(searchHits);
}
I would like to add a filter on the columns. To illustrate in SQL this gives:
Select column_one, column_two from table;

Refer source filtering to fetch only few fields from Elasticsearch query results.
As explained in the same document example below code shows which fields to include and which to exclude.
String[] includeFields = new String[] {"title", "innerObject.*"};
String[] excludeFields = new String[] {"user"};
sourceBuilder.fetchSource(includeFields, excludeFields);

With Spring Data Elasticsearch, you should try this instead:
...
//include only specific fields
final SourceFilter sourceFilter = new FetchSourceFilter(new String[]{"column_one", "column_two"}, null);
// assemble the query
Query searchQuery = new NativeSearchQueryBuilder().withQuery(query).build();
searchQuery.addSourceFilter(sourceFilter);
...

Java equivalent of elasticsearch CURL query?

My project had a new reqiurement of migrating all datas which are currently in postresql to elasticsearch. Successfully migrated all my datas, but I am stuck with writing java code to search for some datas in elastic search index.
Sample structure of a hit in index is attached in the below image:
I need to find average of activity.attentionLevel from the index.
I wrote something like below query to find average:
GET proktor-activities/_search
{
"aggs" : {
"avg_attention" : {
"avg" : {
"script" : "Float.parseFloat(doc['activity.attentionLevel.keyword'].value)" }
}
}
}
please help me to find java equivalent code for doing the same.
thanks in advance

Using Elastic's RestHighLevel API would be something like this:
// Create the client
RestHighLevelClient client = new RestHighLevelClient(
RestClient.builder(new HttpHost("localhost", 9200, "http")));
// Specify the aggregation request
SearchRequest searchRequest = new SearchRequest("proktor-activities");
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.aggregation(AggregationBuilders
.avg("avg_attention")
.field("activity.attentionLevel"));
searchRequest.source(searchSourceBuilder);
// Execute the aggreagation with Elasticsearch
SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
// Read the aggregation result
Aggregations aggregations = response.getAggregations();
Avg averageAttention = aggregations.get("avg_attention");
double result = averageAttention.getValue();
client.close(); // get done with the client
More information here.

How to remove duplicate search result in elasticsearch when using scroll search?

I am developing a project that integrates Java and Elasticsearch.
And I am using scroll api because of searching a large amount of data.
I want to see unique result( like distint in oracle).
How to remove duplicate search result in elasticsearch?
I searched, but couldn't find the Java version.
My code is like this (this is a just sample code):
final Scroll scroll = new Scroll(TimeValue.timeValueMinutes(1L));
SearchRequest searchRequest = new SearchRequest("posts");
searchRequest.scroll(scroll);
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(matchQuery("title", "Elasticsearch"));
searchRequest.source(searchSourceBuilder);
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT);
String scrollId = searchResponse.getScrollId();
SearchHit[] searchHits = searchResponse.getHits().getHits();
while (searchHits != null && searchHits.length > 0) {
SearchScrollRequest scrollRequest = new SearchScrollRequest(scrollId);
scrollRequest.scroll(scroll);
searchResponse = client.scroll(scrollRequest, RequestOptions.DEFAULT);
scrollId = searchResponse.getScrollId();
searchHits = searchResponse.getHits().getHits();
}
Is there any way to search the data on the elastic without duplication?

Scroll will return all the documents in elasticsearch. You cannot perform distinct operation in elasticsearch
There are two ways to resolve your issue
Field collapsing
It does a group by on different fields and return top 1 document
Terms Aggregation
{
"aggs": {
"t": {
"terms": {
"script": "doc['title.keyword'] + ' '+doc['description.keyword']"
}
}
}
}
Scroll is intended to fetch large number of documents and above options are not for bulk data. So you need to perform distinct operation client side(outside of elastic search)

How to use search_after in Elastic High Level Rest Client for pagination

I am using elastic RestHighLevelClient to talk to ES. I am able to query basic queries. Although i am trying to use teh search_after api to design a paginated api from my front end queries. Although query_after is simple to use in the RestLowLevelClient api, i am not able to figure how to use it in the HighLevel API.
Looks like the lucene api has SearchAfterSortedDocQuery, but i am not able to figure how to use it with the elastic search api. For example: in the code below i initialize SearchAfterSortedDocQuery query but not sure how to use it .
RestHighLevelClient client = ESRestClient.getClient();
SearchRequest searchRequest = new SearchRequest();
SearchSourceBuilder searchSourceBuilder = new SearchSourceBuilder();
searchSourceBuilder.query(QueryBuilders.termQuery("field1",value1));
searchSourceBuilder.query(QueryBuilders.termQuery("field2",value2));
searchSourceBuilder.from(0);
searchSourceBuilder.size(limit);
SortField[] sortFields = new SortField[2];
sortFields[0]= new SortField("field1", SortField.Type.LONG);
sortFields[1]= new SortField("field2", SortField.Type.LONG);
FieldDoc fieldDoc = new FieldDoc(0,0); //Is this correct? how to initialize field doc?
fieldDoc.fields = new Object[2];
fieldDoc.fields[0] = new Long("-156034");
fieldDoc.fields[1] = new Long("2297416849");
SearchAfterSortedDocQuery query = new SearchAfterSortedDocQuery(new Sort(sortFields), fieldDoc);
searchRequest.source(searchSourceBuilder);
searchRequest.indices("index1");
try {
SearchResponse response = client.search(searchRequest, RequestOptions.DEFAULT);
System.out.println(response);
}
catch(IOException e){
System.out.println(e);
}
}

I think instead of you using SearchAfterSortedDocQuery, just set search_after in searchSourceBuilder look like below
searchSourceBuilder.searchAfter(new Object[]{sortAfterValue});
after that use SearchRequest and rest client to get the response
SearchRequest searchRequest = new SearchRequest("index");
searchRequest.types("type");
searchRequest.source(searchSourceBuilder);
SearchResponse searchResponse = client.search(searchRequest, RequestOptions.DEFAULT)
SearchHits hits = searchResponse.getHits();
final you should keep the last sort value by getSortValues() from hits to go to the next page.
hits.getAt(lastIndex).getSortValues()
Elasticsearch search_after api
hope this help.

Elastic searchquery by multiple value

I am using java QueryBuilder to search values in elasticQuery.Below is my code snippet.
Sample 2 json store in elastic search
{
"dataLayer":"sourcefeed"
}
{
"dataLayer":"sandbox"
}
BoolQueryBuilder qb = QueryBuilders.boolQuery();
qb.must(QueryBuilders.matchQuery("dataLayer",inputValue);
The input value can be either sourcefeed or sandbox or both,Depending on my input Value it should return the output.For single value it is working fine,But if I give input as InputValue="sourceFeed,sandbox" it is not working.Tried termsQuery also but it is not fetching correctly.Kindly help me to solve the problem.
Thanks Prakash

SearchSourceBuilder query = new SearchSourceBuilder();
BoolQueryBuilder boolQueryBuilder = QueryBuilders.boolQuery();
List<QueryBuilder> queryBuilders1 = new ArrayList<QueryBuilder>();
TermsQueryBuilder termsQuery = QueryBuilders.termsQuery("dataLayer.keyword", listOfValues);
queryBuilders1.add(termsQuery);
boolQueryBuilder.must(queryBuilders1.get(0));
query.query(boolQueryBuilder);
add sourceFeed and sandbox etc in one list and pass it in QueryBuilders.termsQuery.
Try this.Hope this will work.